To meet requirements of a user for a high data transmission rate, user equipment (UE) may access a 3rd Generation Partnership Project (3GPP) network and a non-3GPP network at the same time. The non-3GPP network includes a wireless local area network (WLAN), Worldwide Interoperability for Microwave Access (WiMax), and the like. Previously, when performing service transfer, a UE selects by itself a WLAN access point (AP) as a target access point for service transfer, and therefore, multiple UEs may choose to access a same WLAN access point in a crowded place such as an airport departure lounge or a shopping mall. As a result, the WLAN access point is overloaded soon, and service quality of the WLAN access point deteriorates soon.
To resolve the foregoing problem, in a solution provided in the prior art, a UE fails to select a WLAN access point by itself, but a 3GPP network side directly assists or controls the UE to select the WLAN access point. The 3GPP network side may obtain information about multiple WLAN access points, and therefore, that the 3GPP network side assists or controls a terminal to select a WLAN access point can improve service transfer efficiency of the terminal.
However, in the foregoing solution of the prior art, a policy used by the 3GPP network side to assist or control the UE to select a WLAN access point may be inappropriate, or the UE selects a WLAN access point according to another policy but not a policy sent by the 3GPP network side, which results in a waste of system resources of a 3GPP network. In addition, currently, the 3GPP network side does not know whether the UE selects a proper WLAN and cannot optimize assistance information.